Enhancing salt tolerance in quinoa by halotolerant bacterial inoculation

2016 ◽  
Vol 43 (7) ◽  
pp. 632 ◽  
Author(s):  
Aizheng Yang ◽  
Saqib Saleem Akhtar ◽  
Shahid Iqbal ◽  
Muhammad Amjad ◽  
Muhammad Naveed ◽  
...  

Quinoa is a facultative halophytic seed crop of increasing interest worldwide. Its performance declines under high salinity but can be improved by using halotolerant plant growth-promoting bacteria (PGPB) containing multi-traits, i.e. ACC-deaminase activity, exopolysaccharide secretion and auxin production. This study focussed on improving the productivity of quinoa through the use of six plant growth-promoting bacterial strains (both endophytic and rhizosphere). These were screened by conducting osmoadaptation assay, and the two most halotolerant strains (Enterobacter sp. (MN17) and Bacillus sp. (MN54)) were selected. These two strains were evaluated for their effects on growth, physiological characters and yield of quinoa. At the five leaf stage plants were irrigated with saline water having either 0 or 400 mM NaCl. The results indicated that saline irrigation significantly decreased the growth of quinoa, whereas inoculation of plants with MN17 and MN54 mitigated the negative effects of salinity by improving plant water relations and decreasing Na+ uptake, which consequently, reduced osmotic and ionic stress. Strain MN54 performed better than MN17, which might be because of its better growth promoting traits and higher rhizosphere colonisation efficiency than MN17. Our results suggest that growth and productivity of quinoa could be improved by inoculating with highly tolerant PGPB strain in salt-affected soils.

Plants ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 912
Author(s):  
Shuming Liu ◽  
Hongmei Liu ◽  
Rui Chen ◽  
Yong Ma ◽  
Bo Yang ◽  
...  

Miscanthus spp. are energy plants and excellent candidates for phytoremediation approaches of metal(loid)s-contaminated soils, especially when combined with plant growth-promoting bacteria. Forty-one bacterial strains were isolated from the rhizosphere soils and roots tissue of five dominant plants (Artemisia argyi Levl., Gladiolus gandavensis Vaniot Houtt, Boehmeria nivea L., Veronica didyma Tenore, and Miscanthus floridulus Lab.) colonizing a cadmium (Cd)-contaminated mining area (Huayuan, Hunan, China). We subsequently tested their plant growth-promoting (PGP) traits (e.g., production of indole-3-acetic acid, siderophore, and 1-aminocyclopropane-1-carboxylate deaminase) and Cd tolerance. Among bacteria, two strains, Klebsiella michiganensis TS8 and Lelliottia jeotgali MR2, presented higher Cd tolerance and showed the best results regarding in vitro growth-promoting traits. In the subsequent pot experiments using soil spiked with 10 mg Cd·kg−1, we investigated the effects of TS8 and MR2 strains on soil Cd phytoremediation when combined with M. floridulus (Lab.). After sixty days of planting M. floridulus (Lab.), we found that TS8 increased plant height by 39.9%, dry weight of leaves by 99.1%, and the total Cd in the rhizosphere soil was reduced by 49.2%. Although MR2 had no significant effects on the efficiency of phytoremediation, it significantly enhanced the Cd translocation from the root to the aboveground tissues (translocation factor > 1). The combination of K. michiganensis TS8 and M. floridulus (Lab.) may be an effective method to remediate Cd-contaminated soils, while the inoculation of L. jeotgali MR2 may be used to enhance the phytoextraction potential of M. floridulus.


2015 ◽  
Vol 42 (8) ◽  
pp. 770 ◽  
Author(s):  
Saqib Saleem Akhtar ◽  
Mathias Neumann Andersen ◽  
Muhammad Naveed ◽  
Zahir Ahmad Zahir ◽  
Fulai Liu

The objective of this work was to study the interactive effect of biochar and plant growth-promoting endophytic bacteria containing 1-aminocyclopropane-1-carboxylate deaminase and exopolysaccharide activity on mitigating salinity stress in maize (Zea mays L.). The plants were grown in a greenhouse under controlled conditions, and were subjected to separate or combined treatments of biochar (0% and 5%, w/w) and two endophytic bacterial strains (Burkholderia phytofirmans (PsJN) and Enterobacter sp. (FD17)) and salinity stress. The results indicated that salinity significantly decreased the growth of maize, whereas both biochar and inoculation mitigated the negative effects of salinity on maize performance either by decreasing the xylem Na+ concentration ([Na+]xylem) uptake or by maintaining nutrient balance within the plant, especially when the two treatments were applied in combination. Moreover, in biochar-amended saline soil, strain FD17 performed significantly better than did PsJN in reducing [Na+]xylem. Our results suggested that inoculation of plants with endophytic baterial strains along with biochar amendment could be an effective approach for sustaining crop production in salt-affected soils.


Agronomy ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 888
Author(s):  
Giorgia Novello ◽  
Patrizia Cesaro ◽  
Elisa Bona ◽  
Nadia Massa ◽  
Fabio Gosetti ◽  
...  

The reduction of chemical inputs due to fertilizer and pesticide applications is a target shared both by farmers and consumers in order to minimize the side effects for human and environmental health. Among the possible strategies, the use of biostimulants has become increasingly important as demonstrated by the fast growth of their global market and by the increased rate of registration of new products. In this work, we assessed the effects of five bacterial strains (Pseudomonas fluorescens Pf4, P. putida S1Pf1, P. protegens Pf7, P. migulae 8R6, and Pseudomonas sp. 5Vm1K), which were chosen according to their previously reported plant growth promotion traits and their positive effects on fruit/seed nutrient contents, on a local onion cultivar and on zucchini. The possible variations induced by the inoculation with the bacterial strains on the onion nutritional components were also evaluated. Inoculation resulted in significant growth stimulation and improvement of the mineral concentration of the onion bulb, induced particularly by 5Vm1K and S1Pf1, and in different effects on the flowering of the zucchini plants according to the bacterial strain. The present study provides new information regarding the activity of the five plant growth-promoting bacteria (PGPB) strains on onion and zucchini, two plant species rarely considered by the scientific literature despite their economic relevance.


2007 ◽  
Vol 53 (12) ◽  
pp. 1291-1299 ◽  
Author(s):  
Youai Hao ◽  
Trevor C. Charles ◽  
Bernard R. Glick

In addition to the well-known roles of indoleacetic acid and cytokinin in crown gall formation, the plant hormone ethylene also plays an important role in this process. Many plant growth-promoting bacteria (PGPB) encode the enzyme 1-aminocyclopropane-1-carboxylate (ACC) deaminase, which can degrade ACC, the immediate precursor of ethylene in plants, to α-ketobutyrate and ammonia and thereby lower plant ethylene levels. To study the effect of ACC deaminase on crown gall development, an ACC deaminase gene from the PGPB Pseudomonas putida UW4 was introduced into Agrobacterium tumefaciens C58, so that the effect of ACC deaminase activity on tumour formation in tomato and castor bean plants could be assessed. Plants were also coinoculated with A. tumefaciens C58 and P. putida UW4 or P. putida UW4-acdS– (an ACC deaminase minus mutant strain). In both types of experiments, it was observed that the presence of ACC deaminase generally inhibited tumour development on both tomato and castor bean plants.


2010 ◽  
Vol 56 (No. 12) ◽  
pp. 570-573 ◽  
Author(s):  
D. Egamberdieva

In this study the plant growth-promoting bacteria were analysed for their growth-stimulating effects on two wheat cultivars. The investigations were carried out in pot experiments using calcareous soil. The results showed that bacterial strains Pseudomonas spp. NUU1 and P. fluorescens NUU2 were able to colonize the rhizosphere of both wheat cultivars. Their plant growth-stimulating abilities were affected by wheat cultivars. The bacterial strains Pseudomonas sp. NUU1 and P. fluorescens NUU2 significantly stimulated the shoot and root length and dry weight of wheat cv. Turon, whereas cv. Residence was less affected by bacterial inoculation. The results of our study suggest that inoculation of wheat with Pseudomonas strains can improve plant growth in calcareous soil and it depends upon wheat cultivars. Prior to a selection of good bacterial inoculants, it is recommended to select cultivars that benefit from association with these bacteria.


2001 ◽  
Vol 47 (4) ◽  
pp. 368-372 ◽  
Author(s):  
Donna M Penrose ◽  
Bernard R Glick

It was previously proposed that plant growth-promoting bacteria that possess 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase could utilize ACC that is present in the exudate of germinating canola seeds. The uptake and cleavage of ACC by these bacteria would lower the level of ACC, and thus ethylene within the plant, and reduce the extent of its inhibition on root elongation. To test part of the above mentioned model, ACC levels were monitored in canola seed tissues and exudate during germination. Lower amounts of ACC were present in the exudate and tissues of seeds treated with the plant growth-promoting bacterium Enterobacter cloacae CAL3, than in control seeds treated with MgSO4. The ACC-related compounds, α- and γ-aminobutyric acids, both known to stimulate ethylene production, were also measured in the canola seed exudate and tissues. Approximately the same levels of α-aminobutyric acid were present in the exudates of the bacterium-treated seeds and the control seeds, but the amount of α-aminobutyric acid was lower in the tissues of the bacterium-treated seeds than in the control seeds. Smaller quantities of γ-aminobutyric acid were seen in both the exudate and tissues of the E. cloacae CAL3-treated seeds than in the control seeds.Key words: ACC ethylene, canola, seed extract, seed exudate, plant growth-promoting bacteria.


2001 ◽  
Vol 47 (8) ◽  
pp. 698-705 ◽  
Author(s):  
Saleema S Saleh ◽  
Bernard R Glick

The plant growth-promoting bacteria Enterobacter cloacae CAL2 and UW4 were genetically transformed with a multicopy plasmid containing an rpoS or gacS gene from Pseudomonas fluorescens. The transformed strains were compared with the nontransformed strains for growth, indoleacetic acid (IAA) production, antibiotic production, 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase activity, siderophore production, cell morphology, and the ability to promote canola root elongation. All transformed strains had a longer lag phase, were slower in reaching stationary phase, and attained a higher cell density than the nontransformed strains. Transformation resulted in cells that were significantly shorter than the nontransformed cells. The transformed strains also produced significantly more IAA than the nontransformed strains. Introduction of rpoS or gacS from Pseudomonas fluorescens was associated with a reduction in the production of both antibiotics, 2,4-diacetylphloroglucinol and mono-acetylphloroglucinol, produced by Enterobacter cloacae CAL2. With Enterobacter cloacae CAL2, plasmid-borne rpoS, but not gacS, increased the level of ACC deaminase activity, while introduction of rpoS in Enterobacter cloacae UW4 caused a decrease in ACC deaminase activity. Neither gacS nor rpoS significantly affected the level of siderophores synthesized by either bacterial strain. Overproduction of either GacA or RpoS in Enterobacter cloacae CAL2 resulted in a significant increase in the root lengths of canola seedlings when seeds were treated with the bacteria, and overproduction of RpoS caused an increase in canola shoot as well as root lengths.Key words: plant growth-promoting bacteria, canola, ethylene, ACC deaminase, GacS, RpoS, indoleacetic acid, siderophores, antibiotics.


PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e6076 ◽  
Author(s):  
Hadia -e- Fatima ◽  
Ambreen Ahmed

Bacteria are tiny organisms which are ubiquitously found in the environment. These microscopic living bodies are responsible for the flow of nutrients in biogeochemical cycles and fertility imparted to the soil. Release of excessive chromium in agricultural soils due to rapid growth of industries may result in minimizing the fertility of soil in future, which will lead to reduction in crop production. Plant growth promoting bacteria (PGPB) are beneficial to the environment, some of which can tolerate chromium and protect plants against heavy metal stress. The current study aims to identify such chromium-tolerant auxin-producing rhizobacteria and to investigate their inoculation effects on the growth characteristics of Lens culinaris in chromium polluted soils by using two different chromium salts i.e., K2Cr2O7 and K2CrO4 in varying concentrations (0, 50, 100, 200, 400 and 500 µgml−1). The results revealed that Bacillus species are efficient in significantly reducing the deleterious effects of Cr. These effective bacterial strains were able to stimulate the growth of metal effected plants of Lens culinaris which were grown in chromium contaminated environment. Therefore, these plant growth promoting rhizobacteria PGPRs, having both auxin production potential and chromium-resistance ability, are considered as efficient micro-factories against chromium pollution.


2021 ◽  
Vol 8 (sp1) ◽  
pp. 17-24
Author(s):  
Tanvir Kaur ◽  
Rubee Devi ◽  
Divjot Kour ◽  
Ashok Yadav ◽  
Ajar Nath Yadav

Potassium (K) is the foremost macronutrients for growth of plant, soil health and fertility. The huge application of NPK chemical fertilizers negatively impacts the economy and is a threat to environmental sustainability. The rapid depletion of K mineral in soil is due to the application of agrochemicals agricultural fields for the production of crops in India. In present investigation, K-solubilizing microbes (KSM) were isolated and enumerated from cereal crops growing in Sirmour Himachal Pradesh. A total 125 bacteria were isolated and screened for K- solubilization on Aleksandrov agar plates and found that 31 bacterial strains exhibited K-solubilization. These 31 K-solubilizing strains of bacteria were additionally screened for other plant growth promoting (PGP) potential including solubilization of minerals, production of siderophores, ammonia, hydrogen cyanide and indole acetic acids. The performance of an efficient K-solubilizer was evaluated for plant growth promoting ability in pot assay under in vitro conditions. The strain EU-LWNA-25 positively influenced shoot length, fresh weight, carotenoids and total sugar content than the full dose, half dose and control. The strain enhancing physiological and growth parameters was identified by BLASTn analysis as Pseudomonas gessardii EU-LWNA-25. K-solubilizing plant growth promoting bacteria could be suitable bioinoculants for Rabi seasonal crops and overcomes the challenges of sustainable agriculture in K-deficient soil.


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